We started today before the crack of dawn, deploying a “benthic elevator” over the side of the Western Flyer, and allowing it to sink down 3,200 meters to the seafloor. A benthic elevator is basically a big platform used to carry gear from the surface down to the seafloor, or back from the seafloor up to the surface - sort of like an underwater pickup truck. We sink it with extra weights at the surface, then remove these weights when ready, so that it will float back to the surface.

We knew we’d need the benthic elevator for today’s dive because we planned to bring a couple dozen logs up to the surface. We placed these logs on the seafloor during two previous expeditions, in 2008 and 2010.

Here is the “benthic elevator” that we used to carry mesh bags down to the seafloor and lift bags of logs back up to the surface. Empty bags are on the right. A few full bags are on the left.

You are probably wondering why scientists would sink logs to the deep sea. We are trying to find clues as to how animals make a living in the cold, dark waters, thousands of meters below the surface. The source of almost all of the energy (food) for these deep-sea animals is a “rain” of organic debris that sinks down from the surface. This food includes any and all organic matter that sinks – from fish poop to the bodies of anything from algae to anchovies to whales. It also includes all sorts of debris that washes out to sea from rivers – such as logs.

Many species living on the deep seafloor depend upon “food-falls”– relatively large hunks of food that sink down from the surface like organic meteorites, to plunk down on the muddy bottom. That’s when the keen chemosensory abilities of deep-sea scavengers come in handy–if you can sense and find one of these food falls quickly, you can feed before it is eaten by other animals, meaning more energy to grow and reproduce.

This photo shows one of the smaller logs we picked up today (the red dots are about 29 centimeters—one foot—apart). The log is encased in mesh that keeps out large animals, but doesn’t stop squat lobsters, brisingid sea stars, and anemones from living on the outside. Inside the mesh you can see white worms that have burrowed into the wood.

Natural selection for scavenging abilities almost certainly acts to fine tune the ability of such deep-sea dumpster divers to act quickly and efficiently to find food falls. So much so that some animals specialize in colonizing particular types of food falls, such as dead marine mammals, or sunken pieces of wood.

That’s one reason why we sunk about 36 small logs 50 miles from shore in the outer reaches of Monterey Canyon - to find out whether different types and sizes of wood attract specific types of deep-sea scavengers. We don’t really know if deep-sea animals have divided up this resource among themselves or if all wood specialists will consume just about any type of wood.

This “frame grab” from ROV Doc Rickett’s video camera shows one of the ROV’s manipulator arms holding a mesh bag while the copilot uses the other arm to try and place a big chunk of wood into the bag. It is quite a juggling act, but the ROV pilots did a great job!

We launched the Doc Ricketts around 6:30 in the morning. It arrived on the seafloor, 3,200 meters below, around 8:30 a.m.. Almost immediately we saw a pile of something on the seafloor in the distance, surrounded by a mat of white bacteria. The pile turned out to be the decaying skeleton of a California sea lion. The entire skeleton had been picked clean of all tissue, and the bones were starting to decay.

The decaying sea lion bones were also covered with a mat of reddish fuzz. From previous research at MBARI, we knew that this “fuzz” was a colony of “bone-eating worms.” These worms, in the genus Osedax, quickly colonize and consume the bones of dead animals on the seafloor. We collected a couple of these bones for our colleagues, who are studying these odd worms. But we knew had a lot to do, so we moved on to locate the benthic elevator.

Chris Lovera stuggles to hold up a water-logged log (still in its mesh covering) in order to weigh it in the lab.

We soon found the elevator, which fortunately had landed very close to our sunken logs. Since we hadn’t seen these logs in several years, we were anxious to see what had happened. On the benthic elevator were a number of specially-designed mesh bags, with metal rings around the openings, and handles, which looked a little like short-handled butterfly nets. We planned to use these to collect the logs and any animals that were living in or on them.

Using one of the ROV’s manipulator arms, we pulled one bag off the elevator and moved to the first log. It was still decaying, and had numerous small crabs, worms, and a host of other scavengers on it. We collected some close-up video footage of the log, then picked it up carefully with one manipulator arm and placed it into a fine mesh bag held by the other manipulator arm. This is a tricky operation because the ROV copilot can only operate one arm at a time.

Slowly but surely, we repeated this process all day long. In the end we had collected 23 logs. We loaded the final log on the elevator at about 5:00 p.m., then released the weights holding the elevator to the seafloor. It lifted off of the seafloor and rose toward the surface. The elevator took a little over two and a half hours to reach the surface.

Kurt Buck looks on as Craig McClain picks tiny animals from one of the logs we brought back after three years on the seafloor.

After dinner, we lifted the benthic elevator onto the back deck of the Western Flyer. Then we removed all the bags and logs. As of 10:00 p.m., we are still engaged in the time-consuming process of inspecting, weighing, and photographing each log and picking, cataloging, and preserving all animals we can find, from relatively large crabs to the tiniest of worms and snails. It will take us months to finish our analysis of the logs. At that point, we hope to be able to answer some of the questions posed above.

The R/V Western Flyer is a small water-plane area twin hull (SWATH) oceanographic research vessel measuring 35.6 meters long and 16.2 meters wide. It was designed and constructed for MBARI to serve as the support vessel for ROV operations. Her missions include the Monterey Bay as well as extended cruises to Hawaii, the Gulf of California, and the Pacific Northwest.

ROV Doc Ricketts

ROV Doc Ricketts is MBARI's next generation ROV. The system breaks new ground in providing an integrated unmanned submersible research platform, with many powerful features providing efficient, reliable, and precise sampling and data collection in a wide range of missions.

Push cores

A push-core looks like a clear plastic tube with a rubber handle on one end. Just as its name implies, the push core is pushed down into loose sediment using the ROV's manipulator arm. As the sediment fills up the core, water exits out the top through one-way valves. When the core is pulled up again, these valves close, which (most of the time) keeps the sediment from sliding out of the core tube. When we bring these cores back to the surface, we typically look for living animals and organic material in the sediments.

Benthic respirometer system

Oxygen consumption (a measure of biological activity) of the organisms living in the sediment is measured using a benthic respirometer system (BRS). This instrument is used in situ (in place on the seafloor).

Jim Barry's research program focuses on the effects of climate change on ocean ecosystems. In addition to climate change, his research interests are broad, spanning topics such as the biology and ecology of chemosynthetic biological communities in the deep sea, coupling between upper ocean and seafloor ecosystems in polar and temperate environments, the biology of deep-sea communities, and the biology of submarine canyon communities. Jim has helped inform Congress on ocean acidification, ocean carbon sequestration, and climate change by speaking at congressional hearings, briefings and meetings with congressional members.

Kurt Buck specializes in quantitative enumeration, ecology, and imaging of marine protists and bacteria. Upper water-column communities from Antarctic and Arctic sea ice to equatorial regions were his initial focus. He is currently working with deep-sea sediment communities including those from hypoxic zones.

Patrick has worked at MBARI since its beginning in the fall of 1987. Prior to his move to MBARI, he spent seventeen years at Duke University Marine Lab investigating heavy metals in the marine environment. He currently works with Jim Barry in the design and construction of sampling gear used on the ROV to collect benthic animals, in addition to processing benthic samples and conducting carbon-hydrogen-oxygen (CHN) analyses.

Chris supports Jim Barry's Benthic Biology and Ecology, and Free-Ocean CO2 Enrichment research projects. On this expedition, Chris's responsibilities are varied, from collection and curation of invertebrates used in Benthic Respiration System metabolic rate and manipulative oxygen and pH studies, to Geographic Information System work, to operation of the dissolved inorganic carbon analyzer. Chris's recent work focuses on the effects of ocean acidification on invertebrate behavior.

Kim Fulton-Bennett works as a public information specialist at MBARI, writing articles and news releases for the institution's web site and working with members of the media on MBARI stories. During this cruise, he will be helping take digital notes about each dive, taking photos of the research activities on board, and helping prepare the daily expedition logs.

Craig McClain

Assistant Director of Science
National Evolutionary Synthesis Center

Jenna Judge

Postdoctoral Student
University of California, Berkeley

Jenna Judge is a doctoral student at University of California, Berkeley who is focusing on diversification patterns in chemosynthetic and biogenic habitats. Two years ago, she sank a collection of 10 different kinds of wood in Monterey Bay during a cruise with the Barry lab. On this trip, she hopes to recover all 28 wood bundles to see what animals have colonized them and whether there are differences between animal community richness and abundance for different wood types.

Rosemary Romero

Doctoral Student
University of California, Berkeley

Rosemary Romero is a doctoral student at University of California, Berkeley studying green tides in San Francisco Bay. She will be helping Jenna Judge recover sunken wood with Jim Barry and his lab members. She is excited for the opportunity to go to sea and to discover what animals have colonized the sunken wood since two years ago.